>>He figured bronze would be highly suceptible to corrosion from the HCl, but that does not seem to be the case.
I hope it's a good Aluminium alloy, can you find out B_H?
It's quite a handsome little ghetto bubbler too.
Technical article referring to chemical resistance of different Cu alloys in industry. (
http://www.key-to-metals.com/ViewArticle.asp?ID=16
)
Abstract about Aluminium-Cu bronze alloy:Aluminum bronzes (C 60600 - C 64400; C 95200 - C 95810) containing 5 to 12% Al have excellent resistance to impingement corrosion and high- temperature oxidation. Aluminum bronzes are used for beater bars and for blades in wood pulp machines because of their ability to withstand mechanical abrasion and chemical attack by sulfite solutions.
In the most of practical commercial applications, the corrosion characteristics of aluminum bronzes are primarily related to aluminum content. Alloys with up to 8% Al normally have completely face-centered cubic structures and a good resistance to corrosion attack. As aluminum con tent increases above 8%, a-b duplex structures appear.
Depending on specific environmental conditions, b phase or eutectoid structure in aluminum bronze can be selectively attacked by a mechanism similar to the dezincification of brasses. Proper quench-and-temper treatment of duplex alloys, such as C62400 and C95400, produces a tempered (b structure with reprecipitated acicular a crystals, a combination that is often superior in corrosion resistance to the normal annealed structures.
Nickel-aluminum bronzes are more complex in structure with the introduction of the K phase. Nickel appears to alter the corrosion characteristics of the b phase to provide greater resistance to dealloying and cavitation-erosion in most liquids.
Aluminum bronzes are generally suitable for service in nonoxidizing mineral acids, such as phosphoric (H3PO4), sulfuric (H2SO4), and HCl; organic acids, such as lactic, acetic (CF3COOH), or oxalic; neutral saline solutions, such as sodium chloride (NaCI) or potassium chloride (KCl); alkalies, such as sodium hydroxide (NaOH), potassium hydroxide (KOH), and anhydrous ammonium hydroxide (NH4OH); and various natural waters including sea, brackish, and potable waters. Environments to be avoided include nitric acid (HNO3); some metallic salts, such as ferric chloride (FeCl3) and chromic acid (H2CrO4); moist chlorinated hydrocarbons; and moist HN3. Aeration can result in accelerated corrosion in many media that appear to be compatible.-------------------
So, what do these pneumatic switches do exactly?